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[Bug middle-end/24408] New: [4.1 Regression] Invariant code no longer removed from loop when doing FDO.
- From: "steinmtz at us dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 17 Oct 2005 15:12:35 -0000
- Subject: [Bug middle-end/24408] New: [4.1 Regression] Invariant code no longer removed from loop when doing FDO.
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
There was some discussion on the GCC mailing list in late August, early
September about a performance regression caused by the disabling of the old
loop optimizer when doing FDO.
http://gcc.gnu.org/ml/gcc/2005-08/msg00899.html
Loop invariant motions done by the old loop optimizer no longer occur. This is
causing a performance regression on some benchmarks.
The following patch enables loop invariant motions during FDO and fixes the
observed performance regression:
http://gcc.gnu.org/ml/gcc-patches/2005-10/msg00224.html
--
Summary: [4.1 Regression] Invariant code no longer removed from
loop when doing FDO.
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: steinmtz at us dot ibm dot com
GCC host triplet: powerpc64-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24408